The present invention relates to the coating of medical devices intended for in vivo deployment and, in particular, it concerns a method and device, which is suitable for use in an operating theater just prior to implantation, for selectively applying a medical coating to an implantable medical device, for example a stent.
The practice of coating implantable medical devices with a synthetic or biological active or inactive agent is known. Numerous processes have been proposed for the application of such a coating. Soaking or dipping the implantable device in a bath of liquid medication is suggested by U.S. Pat. No. 5,922,393 to Jayaraman, soaking in an agitated bath, U.S Pat. No. 6,129,658 to Delfino et al. Devices introducing heat and/or ultrasonic energy in conjunction with the medicated bath are disclosed in U.S. Pat. No. 5,891,507 to Jayaraman and U.S. Pat. No. 6,245,104 B1 to Alt. The device of U.S. Pat. No. 6,214,115 B1 to Taylor et al. suggest spraying the medication by way of pressurized nozzles.
Initially such coating were applied at the time of manufacture. For various reasons such as the short shelf life of some drugs combined with the time span from manufacture to implantation and the possible decision of the medical staff involved concerning the specific drug and dosage to be used based on the patient""s at the time of implantation, have lead to methods and devices for applying a coating just prior to implantation. Wrapping the implantable device with medicated conformal film is disclosed in U.S. Pat. No. 6,309,380 B1 to Larson et al. Dipping or soaking in a medicated bath just prior to implantation are suggested in U.S. Pat. No. 5,871,436 to Eury, U.S. Pat. No. 6,106,454 to Berg et al., and U.S. Pat. No. 6,1171,232 B1 to Papandreou et al. U.S. Pat. No. 6,203,551 B1 to Wu provides a bathing chamber for use with specific implantable device such as the stent deployed on the balloon of a catheter (FIG. 1).
Each of the methods and devices intended for use just prior to implantation, listed above, deposit the coating material onto any and all surfaces that are exposed to the coating. This may result in depositing coating material on surfaces on which the coating is unwanted or undesirable. Further, the coating may crack or break away when the implantable is removed from the implantation apparatus. An example of this would be a stent deployed on a catheter balloon. As the balloon is inflated and the stent is expanded into position, the coating may crack along the interface between the stent and the balloon. These cracks may lead to a breaking away of a portion of the coating from the stent itself. This, in turn, may affect the medicinal effectiveness of the coating, and negatively affect the entire medical procedure.
It is further know to use Ink-Jet technology to apply a liquid to selected portion of a surface. In the paper xe2x80x9cApplications of Ink-Jet Printing Technology to BioMEMS and Microfluidic Systems,xe2x80x9d presented at the SPIC Conference on Microfluidics and BioMEMS, October, 2001, the authors, Patrick Cooley, David Wallace, and Bogdan Antohe provide a fairly detailed description of Ink-Jet technology and the range of its medically related applications (http://www.microfab.com/papers/papers_pdf/spie_biomemsxe2x80x9401_reprint.pdf). A related device is disclosed in U.S. Pat. No. 6,001,311 to Brennan, which uses a moveable two-dimensional array of nozzles to deposit a plurality of different liquid reagents into receiving chambers. In the presentation of Cooley and the device of Brennan, the selective application of the material is based on an objective predetermined location of deposit rather that on a subjective placement as needed to meet the requirements of a specific application procedure. With regard to the application of coatings applied to medical devices with ink-jet applicators, while it is possible to coat only a chosen portion of a device, such as only the stent mounted of a catheter, but not the catheter itself. This type of procedure using current device may, however, require providing complex data files, such as a CAD image of the device to be coated, and insuring that the device be installed in the coating apparatus in a precise manner so as to be oriented exactly the same as the CAD image.
There is therefore a need for a device, and method for its use, whereby.a coating is selectively applied to an implantable medical device just prior to implantation, such that only the device or selected portions thereof are coated. It would be desirable for the device to provide for user selection of coating material and dosage to be applied, thereby providing choices as to the specific coating material and dosage to be applied based on the specific needs of the patient at the time of implantation. It would be further desirable for the device to provide a sterile environment in which the coating is applied and the device is suitable for use in an operating theater.
The present invention is a method and device, which is suitable for use in an operating theater just prior to implantation, for selectively applying a medical coating to an implantable medical device, for example a stent.
According to the teachings of the present invention there is provided, a coating device for selectively applying a coating to surfaces of an object, the device applying the coating based upon optical properties of the surfaces such that the coating is applied to surfaces of a first type and is not applied to surfaces of a second type, the first type of surface being optically distinguishable from the second type of surface, the coating device comprising: at least one object-holding element configured to hold the object while a coating is applied; at least one optical scanning device deployed so as to scan at least a portion of the object, the optical scanning device configured so as to produce output indicative of the types of surfaces of the object; at least one coating applicator deployed so as to deposit a fluid so as to coat at least a portion of the object; at least one fluid delivery system in fluid communication so as to supply the fluid to the coating applicator; a processing unit being responsive at least to the output so as to selectively activate the coating applicator, thereby applying the coating substantially only to surfaces of the first type; and a drive system configured so as to provide relative motion between the surface of the object and the coating applicator, and between the surface of the object and the optical scanning device.
According to a further teaching of the present invention, the drive system is configured so as to rotate the object-holding element about an axis perpendicular to a direction of application of the coating applicator.
According to a further teaching of the present invention, the at least one object-holding element is implemented as two object-holding elements configured so as to simultaneously support the object at two different regions along a length of the object.
According to a further teaching of the present invention, the two object-holding elements are mechanically linked so as to rotate synchronously about a single axis, the axis being perpendicular to a direction of application of the coating applicator.
According to a further teaching of the present invention, the at least one coating applicator includes a pressure-pulse actuated drop-ejection system with at least one nozzle.
According to a further teaching of the present invention, a spatial relationship between the coating applicator and the object is variable.
According to a further teaching of the present invention, the spatial relationship is varied along a first axis that is parallel to a direction of application of the coating applicator, and a second axis that is perpendicular to the direction of application of the coating applicator.
According to a further teaching of the present invention, the coating applicator is displaceable relative to the object-holding element, the displacement being along the first axis and the second axis, thereby varying the spatial relationship.
According to a further teaching of the present invention, both the coating applicator and the optical scanning device are deployed on a displaceable applicator base, displaceable relative to the object-holding element, the displacement being along the first axis and the second axis, thereby varying the spatial relationship.
According to a further teaching of the present invention, the at least one coating applicator is implemented as a plurality of coating applicators and the at least one fluid delivery system is implemented as an equal number of fluid delivery systems, each fluid delivery system supplying a different fluid coating material to the coating applicator with which the each fluid delivery system is in fluid communication.
According to a further teaching of the present invention, the object is a catheter that includes a balloon portion on which a stent is deployed, such that the stent is a surface of the first type and the balloon is a surface of the second type surface.
According to a further teaching of the present invention, the processing unit is responsive to an indication of the relative motion so as to change operational parameters of the coating device as required.
According to a further teaching of the present invention, the object-holding element, the coating applicator, the optical scanning device, the drive system and at least a portion of the fluid delivery system are deployed within a housing that includes an application compartment.
According to a further teaching of the present invention, the housing includes a base housing section and a detachable housing section.
According to a further teaching of the present invention, the application compartment is defined by portions of both the base housing section and the detachable housing section.
According to a further teaching of the present invention, the base housing section includes the coating applicator, at least a portion of the fluid delivery system, the optical scanning device and the processing unit and at least a first portion of the drive system, and the detachable housing section includes the object-holding element and at least a second portion of the drive system.
According to a further teaching of the present invention, the base housing section includes at least one fluid delivery system.
According to a further teaching of the present invention, the detachable housing section is disposable.
According to a further teaching of the present invention, the application compartment is a substantially sterile environment.
According to a further teaching of the present invention, the coating applicator, and the fluid delivery system are included in a removable sub-housing, the removable sub-housing being deployed with in the application compartment and the removable housing being detachably connected to the processing unit.
There is also provided according to the teachings of the present invention, a coating device for selectively applying a coating to surfaces of an object, the device applying the coating based upon optical properties of the surfaces such that the coating is applied to surfaces of a first type and is not applied to surfaces of a second type, the first type of surface being optically distinguishable from the second type of surface, the coating device comprising: a) a housing which includes an application compartment; b) at least one object-holding element deployed within the application compartment, the object-holding element configured to hold the object to which a coating is applied; c) a displaceable applicator base deployed within the application compartment, the applicator base including: i) at least one coating applicator aligned so as to deposit a fluid whereby at least a portion of the object is coated; and ii) at least one optical scanning device deployed so as to scan at least a portion of the object, the optical scanning device configured so as to produce output indicative of the different types of surfaces of the object, the displacement of the applicator base resulting in a variance of a spatial relationship between the coating applicator base and the object; d) at least one fluid delivery system in fluid communication so as to supply the fluid to the coating applicator; e) a processing unit being responsive at least to the output so as to selectively activate the coating applicator, thereby applying the coating substantially only to surfaces of the first type; and f) a drive system configured so as to provide relative motion between the surface of the object and the applicator base.
According to a further teaching of the present invention, the housing includes a base housing section and a detachable housing section.
According to a further teaching of the present invention, the application compartment is defined by portions of both the base housing and the detachable housing section.
According to a further teaching of the present invention, the base housing section includes the displaceable applicator base, at least a portion of the fluid delivery system, and the processing unit, and at least a first portion of the drive system, and the detachable housing section includes the object-holding element and at least a second portion of the drive system.
According to a fuirther teaching of the present invention, the base housing section includes at least one fluid delivery system.
According to a further teaching of the present invention, the detachable housing section is disposable.
According to a further teaching of the present invention, the drive system is configured so as to rotate the object-holding element about an axis perpendicular to a direction of application of the coating applicator.
According to a further teaching of the present invention, the at least one object-holding element is implemented as two object-holding elements configured so as to simultaneously support the object at two different regions along a length of the object.
According to a further teaching of the present invention, the two object-holding elements are mechanically linked so as to rotate synchronously about a single axis, the axis being perpendicular to a direction of application of the coating applicator.
According to a firther teaching of the present invention, the at least one coating applicator includes a pressure-pulse actuated drop-ejection system with at least one nozzle.
According to a further teaching of the present invention, the at least one fluid delivery system is deployed in the base housing.
According to a further teaching of the present invention, the at least one coating applicator is implemented as a plurality of coating applicators and the at least one fluid delivery system is implemented as a like number of fluid delivery systems, each fluid delivery system supplying a different fluid coating material to the coating applicator with which the each fluid delivery system is in fluid communication.
According to a further teaching of the present invention, the coating applicator, and the fluid delivery system are included in a removable sub-housing, the removable sub-housing being detachably connected to the displaceable applicator base.
According to a further teaching of the present invention, the spatial relationship is varied along two axes, a first axis that is parallel to a direction of application of the coating applicator, and a second axis that is perpendicular to the direction of application of the coating applicator.
According to a further teaching of the present invention, the object is a catheter that includes a balloon portion on which a stent is deployed, such that the stent is a surface of the first type and the balloon is a surface of the second type.
According to a firrther teaching of the present invention, the processing unit is responsive to an indication of the relative motion so as to change operational parameters of the coating device as required.
There is also provided according to the teachings of the present invention, a coating method for selectively applying a coating to surfaces of an object, the method applying the coating based upon optical properties of the surfaces such that the coating is applied to surfaces of a first type and is not applied to surfaces of a second type, the first type of surface being optically distinguishable from the second type of surface, the coating device comprising: generating relative movement between the object and at least one optical scanning device and at least one coating applicator; optically scanning at least a portion of the object by use of the at least one optical scanning device so as to produce output indicative of the different types of surfaces of the object; responding to the output by selectively activating the coating applicator, thereby applying the coating substantially only to surfaces of the first type.
According to a fuirther teaching of the present invention, the relative movement includes rotating the object about an axis perpendicular to a direction of application of the coating applicator.
According to a further teaching of the present invention, there is also provided simultaneously supporting the object at two different regions along a length of the object.
According to a further teaching of the present invention, the selective activation includes selectively activating a pressure-pulse actuated drop-ejection system with at least one nozzle.
According to a further teaching of the present invention, the selective activation includes selectively activating a pressure-pulse actuated drop-ejection system with at least one nozzle that is included in a removable sub-housing, the removable sub-housing further including a fluid delivery system in fluid communication so as to supply coating material to the coating applicator.
According to a further teaching of the present invention, the applying is preformed by selectively activating one of a plurality of coating applicators, wherein the at least one coating applicator implemented as the plurality of coating applicators, each of the plurality of coating applicators applying a different coating.
According to a further teaching of the present invention, the applying is preformed by selectively activating, in sequence, the plurality of coating applicators, thereby applying a plurality of layered coats, each one of the plurality of layered coats being of a coating material that is different from adjacent layered coats.
According to a further teaching of the present invention, responding to the output includes the output being indicative of a balloon portion of catheter and a stent deployed on the balloon, such that the stent is a surface of the first type and the balloon is a surface of the second type.
According to a further teaching of the present invention, responding to the output includes the output being indicative only of a surface of the first type thereby applying the coating to substantially the entire surface of the object.
According to a further teaching of the present invention, there is also provided varying a spatial relationship between the coating applicator and the object.
According to a further teaching of the present invention, the varying is along two axes, a first axis that is parallel to a direction of application of the coating applicator, and a second axis that is perpendicular to the direction of application of the coating applicator.
According to a further teaching of the present invention, the varying is accomplished by displacing the coating applicator.
According to a further teaching of the present invention, the varying is accomplished by varying the spatial relationship between the object and a displaceable applicator base upon which the at least one coating applicator and the at least one optical scanning device are deployed.
According to a further teaching of the present invention, controlling the varying is accomplished by the processing unit.
According to a further teaching of the present invention, there is also provided responding to an indication of the relative motion so as to change operational parameters of the coating device as required.
According to a further teaching of the present invention, generating relative movement, the optically scanning at least a portion of the object, and the selectively activating the coating are preformed within a housing.